Myth 6: QCT has poor precision

This may have been a problem back in the 1990’s when 2D QCT spine bone density measurements relied on gantry tilt to orient a single scan slice through the middle of a vertebral body. That process was very operator-dependent and less to reproducibility issues. Nowadays, QCT exams use volumetric scan data so that any spine or hip orientation correction can be dealt with in software. Published short-term precision estimates of BMD measurement by volumetric QCT have been calculated as CV% for BMD at the lumbar spine (0.8%) and areal BMD at the total hip (0.82%) and femoral neck (0.69%). This compares favorably with DXA areal BMD measurements, for which published precision estimates are similar for the lumbar spine (1.1%), total hip (0.65%) and femoral neck (1.66%).